They used to be fairly dense with information, well explained, and coherent. Now they seem to be filled with irrealavant and distracting fluff that isn't of no use to the student.
I had my cousin over for a visit today, and he had me help him with some of his trig homework. The textbook they were having him read was complete and utter garbage compared to the textbook I had that was published in 84.
Why do they give students today's such shitty textbooks? Why the hell are they still even publishing new editions of books covering basic concepts like trigonometry... Comment too long. Click here to view the full text.
>>8455707 HEY GUYS, LET'S BUILD A CAPITALIST ECONOMIC SYSTEM IN WHICH THE MEANS OF PRODUCTION OF TEXTBOOKS ARE IN THE HANDS OF LARGE COMPANIES AND MILLIONS UPON MILLIONS OF STUDENTS ARE IN NEED OF TEXTBOOKS EACH YEAR!
>>8455717 The issue isn't capitalism. The issue is the fact school is publicly funded and the free market has zero say in determining matters( such as what textbook to use) as there are no penalties in getting it wrong.
>The Sun has fallen out of orbit and is going to crash into the Earth. Humanity has randomly chosen people to enter an underground nuclear shelter with enough food and provisions for the next 50 years until the Earth is habitable again, luckily you were picked. >You are allowed to bring one scientific instrument with you.
It's still like 15 years away from full operation. And that's assuming no more setbacks. It has already been pushed back a lot from original estimates.
Assuming it works, it's still only a proof of concept--- that concept being a fusion reactor that puts out more energy than is put in. It would be up to its successors to "blow every other clean energy argument out". It would still be awesome.
>>8455519 Fusion research is great, but I can't see this (or anything similar) as ever being viable as a practical energy source.
Fast neutrons make it much harder to get useful energy out, as well as making radiation shielding a nightmare. Capital cost will be astronomical (capital servicing is the primary operating cost for fission).
What problem does this solve that fission isn't a better solution for?
IMO, fusion power is only going to be viable if we can get aneutronic fusion working, and... Comment too long. Click here to view the full text.
Can someone explain (or prove, though not required) why two intersecting perpendicular lines diagonally across a plane with an infinitely small circle of radius r in the center does not disprove the Four Color Theorem? In the middle do they all not touch and either two sections of the four quadrants would be forced to touch along the sides, or through the center, or standing as it is in pic related where the four quadrants support the Four color theorem, the circle that is colored any color would touch one of the four quadrants?
Also >infinitely small circle of radius r while you shouldn't even fall for the Descartes meme of thinking it needs points to make up for lines and planes, please don't reason with infinitesimals like properties for finite things apply to them
In mathematics, the four color theorem, or the four color map theorem, states that, given any separation of a plane into contiguous regions, producing a figure called a map, no more than four colors are required to color the regions of the map so that no two adjacent regions have the same color. Two regions are called adjacent if they share a common boundary that is not a corner, where corners are the points shared by three or more regions.
>>8455444 By GMO OP obviously means taking genes and segments of DNA from one species and putting them into another species. What we have been doing for thousands of years is artificially breeding plants and animals for select traits we desire instead of leaving them subject to natural selection.
What's does /sci/ thinks of spirit cooking and the latest wiki leaks shit saying Hillary is involved in satanic rituals? Come on it can't be true r-right? I'm that kind of guy that if I saw this I would just say go back to >>>/x/ and every part of my brain is screaming that that's a false flag that's there's no supernatural phenomena and that I'm a faggot for thinking that shit is possible. But I'm kinda scared this shouldn't be happening to me. I'm a physicist for gods sake.
One famous one is about the claim that a set which has more elements then the natural numbers but less then the real numbers. It has been proven that it is impossible to construct such a set but it is also impossible to proove that such a set does not exist.
To elaborate further:
If you are not familiar with the idea of sets they basically represent a "bucket" which contains "things" called elements.
If these "Buckets" have finite elements there are two ways to compare how many elements. You could could count the elements... Comment too long. Click here to view the full text.
Caltech researchers have found evidence suggesting there may be a "Planet X" deep in the solar system. This hypothetical Neptune-sized planet orbits our sun in a highly elongated orbit far beyond Pluto. The object, which the researchers have nicknamed "Planet Nine," could have a mass about 10 times that of Earth and orbit about 20 times farther from the sun on average than Neptune. It may take between 10,000 and 20,000 Earth years to make one full orbit around the sun.
"The possibility of a new planet is certainly an exciting one for me as a... Comment too long. Click here to view the full text.
>>8455047 >>8455038 what is this, are you doing this in university op ? i was doing this shit in 10th grade. please tell there's more to uni that this, or i'll go straight into pure math, even if i fail it
>>8455247 it's the process of using neural networks to uncover the latent manifold on which some collection of data lies, once you have said manifold you can do things like hop around on it and sample fake data that closely resembles real data.
for example, here are some generated images of bedrooms from a bedroom manifold.
and here's a paper that improves superresolution techniques by projecting an enhanced image onto a manifold of natural images https://arxiv.org/abs/1609.04802
You know, looking at this picture you can't help but think that in at least 1 galaxy there's some alien civilization, probably advanced enough to go around planets and starts (via cryostasis or whatever) and establish colonies. Humanity one day might do the same, it's fine. Thing is, we're never going to meet aliens, it's just too unlikely. Crossing galaxies is going to take a fuckton of years and even then, when you arrive, the galaxies are absolutely fucking huge. And the inverse square law is such a bitch and makes radiowaves decay so quickly its... Comment too long. Click here to view the full text.
>>8454858 After researching it I've come to the conclusion that it's not unhealthy at all, certain groups that try to push a biased scientific view of smoking basically cherry pick the shit out of their studies and data, while completely downplaying the role that certain transmittable diseases have in causing so called smoking-related illnesses. It's called confounding by infectious disease.
What is it being a graduate student? One of TAs who is a grad student says that now that she's experienced being one, she would never recommend it to anyone who might be considering it. She also always seems pretty lifeless and gloomy, but I don't know if that's her as a person.
>Watching grad student present his thesis topic. >Using FEM to model something. >Decides he should explain FEM to the room. >Draws xy axes and a curve. >Draws rectangles under the curve. >Says we approach the real solution as the width of each rectangle approaches 0 or as the number of rectangles approaches infinity.
Was he memeing? Because that seemed a lot like a Riemann sum.
Was it his whole thesis or just something he used in passing ? I mean Riemann sums *are* used to compute integrals, I dunno why kids here are so shocked to hear that grad students use elementary tools (especially in non-math fields). Research is not about revolutionizing science every day, it's about using knowledge that exists to answer your own dumb questions.
>>8454844 You should not have to present something as basic as integration to a thesis defense committee and the rest of the audience at the graduate level. Maybe in a freshman course but not graduate. If someone doesn't know how integration works tell them to ask a freshman calc student to explain it to them
>>uni student doing undergrad research on concrete
It's actually quite impressive all the admixtures and reinforcements available on the market
The big problem is, either you have concrete that is rated 14ksi and performs absolutely horrible under elevated temperatures, or concrete that can endure 700°C but loses 80% of its compressive strength post heat.
Also; has anyone heard of concrete that's repairs itself being exposed to water?
>>8454788 That is some cool shit, where are you going to uni? I interned in rock mechanics this summer, so I ran a lot of compressive strength tests with rock cores. Worked pretty closely with a concrete engineer though.
So i was checking out Cauchy's rigidity theorem, which basically says that any convex polyhedron is rigid. This statement is however not true for a non-convex polyhedron. There may be some continuous deformation that leaves sides and faces intact, but changes angles between faces. A well known example of this by Klaus Steffen can be found in the image.
Now Idjad Sabitov proved further that, although such a continuous deformation changes angles between faces, it does conserve the volume enclosed by those faces.
Here's where i get confused, because this... Comment too long. Click here to view the full text.
Read up on everything you mentioned and came to the same conclusion you did. I agree that this volume is clearly changing while the faces remain rigid. Do you have the original Connelly article / Bellows conjecture? Maybe we don't understand something about the class of non-convex polyhedra they're using.
>>8454782 I found the original proof: https://www.math.ucdavis.edu/~deloera/MISC/BIBLIOTECA/trunk/Connelly/Connelly3.pdf In it they speak of a "flex" of a surface (triangulated). For the definition of a "flex" i find the following article which defines it for graphs representing polyhedra http://erikdemaine.org/papers/LinkageTR/paper.pdf with Connelly as co-writer, leading me to think this must be the proper definition.
However, this doesn't help at all. As you can see in the definition... Comment too long. Click here to view the full text.
>>8454720 That's the one that the axiom of infinity cannot be proven via first principles right?
The inductive set and naturals model a very large finite set pretty well without worrying about just how big that very large set is. Sure you could prove that induction works on every finite set via first principles...but I'm lazy and that sounds boring. ne?
>>8454717 I honestly just don't know how to write it out. Fuck the public school system failed me, i basically winged it through high school. I think my algebra 1 teacher thought I was downright retarded or she wanted my dick. She literally just answered my work for me.
All trademarks and copyrights on this page are owned by their respective parties. Images uploaded are the responsibility of the Poster. Comments are owned by the Poster.
This is a 4chan archive - all of the content originated from them. If you need IP information for a Poster - you need to contact them. This website shows only archived content.
If a post contains personal/copyrighted/illegal content you can contact me at firstname.lastname@example.org with that post and thread number and it will be removed as soon as possible.